Does Invasive Always Equal Evil?

Reader Contribution by David Goodman
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This is probably going to make a lot of people mad, but I have a confession: I think many non-native invasive plants are fantastic.

Before you stone me – let me explain.

The entire planet is in a state of constant flux. Cycles of warming, cooling, extinction, floods, earthquakes, glaciers, volcanoes and sea level changes are part of the system. And inside that complex system, there are constant battles between different species. When we get involved, things are sometimes preserved … and sometimes destroyed. Boats, planes, cars and even footsteps have carried plants, animals and insects into places where they’ve never gone before. Government programs have led to land mismanagement that changes the balance of nature while encouraging the planting of terrible mistakes like kudzu, not to mention the eradication of “pest” species that later turned out to be important to maintaining a healthy ecological balance (remember the Yellowstone wolf eradication program?). Over time, termites have arrived in wooden crates … mosquito larvae traveled in water-filled tires … pretty plants like air potatoes have been spread by unsuspecting little old ladies … weed seeds have traveled in sod… the list goes on and on and on.

It’s enough to give any USDA inspector a major headache. No one wants to see chestnuts fall by the millions to an introduced blight … or watch entire forests be devoured by vines … or worry if a newly arrived beetle is going to spread a killer fungus into their prized avocado tree.

But at the same time – sometimes the cure is worse than the disease. Did you know that Monsanto funds native plant initiatives? It seems that for every “pest” plant that shows up, there’s the same answer: RoundUp! Is killing all these invasive plants the right thing to do?

Perhaps in the case of some of them, we should just let nature find its own path? Even better, what if we put some of the invasives to work for us?

Here’s an example of a useful invasive: the winged yam, also known as Dioscorea alata. Though it’s shown up here and there across the southern states, it’s not a madly prolific invader like its cousin the air potato (Dioscorea bulbifera). It’s also a really good edible, making delicious roots that can become quite large over successive seasons. Last fall I found a vine in the wild, dug it up, and got a succulent 8lb tuber (which was subsequently turned into some of the best home fries we’ve ever had.) At some point, the winged yam was brought here as an edible. And, being a good tough plant, it escaped… and now there’s free food where there didn’t used to be. Yams beat the heck out of acorns, which would probably be the next best source of calories around here.

Yet – when winged yams are found in a park, what happens? Do they get eaten? No – they get sprayed with herbicides. Wouldn’t it make more sense to teach people how delicious they are? Sure, if anyone knew how many delicious calories you could grow with little work, they might start planting the yams and spreading them further… but I’m not at all convinced that’s a bad thing. Of course, it’s not like I’m going around telling everyone how great these things are. Oh … wait …

Now let’s take a look at another invasive plant: the mimosa tree, also known as Albizia julibrissin. In 1745 it was introduced to the US from China and has spread here and there throughout a lot of the woods on the southeast half of the nation. It’s a pretty tree and has been planted extensively as an ornamental. Being a member of the bean and pea family, it also has the gift of fixing nitrogen. Remember how George Washington Carver planted peanuts between crops of cotton to put nitrogen back in the soil? That’s what these guys do – and that’s why you’ll often see mimosa trees by the side of highways. Where the ground has been broken, abused and torn to pieces, these hardy pioneers step in and fix things. They’re a soft-wooded species that’s also a fast-growing source of biomass. If I had a wrecked piece of farmland that had been stripped bare, I’d think about interplanting these suckers with fruit trees. Then I’d chop back the mimosas any time things got too shady. This way, they’d be feeding the ground from beneath thanks to their nitrogen-fixing powers… and they’d be feeding the ground from above thanks to the rough chop-n-drop mulch I’d be making. Having them in the system would contribute greatly to the success of my cultivated fruit trees. Just because they’re “invasive,” it doesn’t mean they’re worthless.

Finally – let’s wrap up with an incredibly obnoxious plant that’s been classified as “invasive,” since it most definitely is: the water hyacinth.

Just say “water hyacinth” and many people cringe. These things can double their population every two weeks, choking out rivers, ponds and waterways, causing terrible amounts of trouble for the tourist industry, shipping and anyone who enjoys boating. They’re not supposed to be in the US – but they’re here now, so we’re stuck. Currently, the plants are being sprayed with herbicides, shredded by special dredgers and completely… wasted.

Wasted? Yeah. The very thing that makes the water hyacinth a terrible weed… its ability to grow at astonishing speeds… is also an incredible asset. How so?


Have you ever fought and fought to make enough compost? Doesn’t it seem like you can never get enough greens and browns together to feed all the plants you want to feed, so you’re stuck doling out compost like a miser? What if – instead of simply poisoning all these water hyacinth plants – they were composted?

Here’s how a friend of a friend does it: There’s a foreclosure home with an abandoned pool. That pool is now home to a mess of water hyacinths. Every week or two, this fellow fills a few 55-gallon drums full of water hyacinth plants, then dumps them in a pile to rot. Once out of the water, the plants begin composting rapidly… and the resulting black gold is used to feed his gardens. How’s that for American ingenuity?

High in protein, water hyacinth can also be used as animal feed – or even human feed. It could also be an amazing source of biofuel, if we re-thought things a bit and quit simply killing it.

Unfortunately, you’re really not allowed to experiment with this at your own place. If I decided to grow water hyacinths, I’d probably be in violation of a half-dozen laws. And not only that – you’re not even allowed to scrape up a bunch from the local river and compost them. Nope – that’s illegally transporting a Terrible Evil Invasive. Instead, we have to pay some poor guy to blast herbicides over the river all day.

Because dealing with invasive plants has become a place for laws, laws, laws, laws, laws and weed killer… it’s sometimes hard for environmentally minded folks with good ideas to re-purpose these plants so they become assets.

Many of the problems with invasive species are our own fault. And now it’s up to us to take these species and use them in the best manner possible while still preserving native plants to the best of our ability. There may be times we need to go full-on scorched earth with non-native invasives … but I’ll bet it’s a lot less often than we do now.

Perhaps rather than reaching for the backpack sprayer, we should start searching for new uses (and recipes) for troublesome species?

Yam hashbrowns, anyone?

For survival plant profiles, ideas on growing tons of food, and madcap gardening inspiration, visit David’s daily blog

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